Automatic choke-valve control for gas engines



Aug. 20,v l929. A, M HARBlSQN 1,725,513

AUTOMATIC CHOKE VALVE CONTROL FOR GAS ENGINES Fild Aug. 26, 192e 2sheets-sheet 1 Aug. 20, 1929. A. M. HARBlsoN AUTOMATIC CHOKE VALVECONTROL FOR GAS ENGINES Filed Aug. 26, 1926 2 Sheets-Sheet 2 PatentedAug. 20, 1929.

UNITED STATES 1,725,513 PATENT OFFICE.

ARTHUR M. HABBISON, 0F IBOGGSVILLE, PENNSYLVANIA, ASSIGNOR 0F ONE-HAL]lT0 GUY BUNDY, 0F WEST WINFIELD, PENNSYLVANIA.

AUTOMATIC CHOKE-VAL'VE CONTROL FOB GAS ENGDES.

Application led August 26, 1926. Serial No. 131,720.

This invention relates to improvements in automatic chokes for thecarbureters of internal combustion engines and has as its general objectlto provide means for automatically controlling the choke valve toregulate the supply of air to the carbureter automatically in consonancewith the operation of the engine.

Another object of the invention is to provide an automatic choke soconstructed as to obviate' the necessity of manually adjusting the chokevalve to substantially closed position at the time of starting theengine in cold weather, and which means will operate automatically toopen the choke valve to the proper extent as soon as the engine starts,so that no attention of the driver to the adjustment of the choke valveis required.

Another object of the invention is to -provide an automatic choke whichwill depend for its automatic functioning on the partial vacuum ornegative pressurel in the intake manifold of the engine, so that thechoke valve will be automatically adjusted in accordance with therequirements of the engine under different running conditions.

Another object of the invention is to provide an yautomatic chokemechanism which may be readily installed upon the intake manifold andreadily connected to the choke lever of the carbureter.

In the accompanying drawings:

Figure 1 is a side elevation of the automatic choke embodying theinvention installed upon the intake manifold and carbureter of aninternal combustion engine.

Figure 2 is a detail horizontal sectional view through the mechanism.

Figure 3 is a vertical longitudinal sectional view in detail through themechanism.

Figure 4 is a view in elevation looking at one end of the mechanism.

Figure 5 is a similar view looking at the other end of the mechanism.

Figure 6 is a det-ail sectional view illustrating a part of themechanism.

In the drawings, the numeral 1 indicates the intake manifold, thenumeral 2 the carbureter, the numeral 3 the usual shaft upon which thechoke valve is mounted, and vthe numeral 4 the arm which is ordinarilyfixed upon this shaft. All of this structure is, of course, old andconstitutesv no part of the present invention, the only change in theconstruction being that the usual spring which is connected with the arm4 and which normally holds the shaft 3 in position with the choke valveopen, is omitted.

The mechanism includes a small cylinder 5 closed at one end by a head 6and at its other end'bya head 7 and the head 6 has a. branch lwhichextends upwardly and accommodates one end of an elbow 8, the other endarranged in the outer end of the opening so as to provide asubstantially air-tight packing about the stem. A spring 14 is arrangedupon the stem of the piston and bears at one end against the inner endof the head 6 of the cylinder and at its other end against the head ofthe piston, and this spring normally holds the piston in substantiallythe position shown in Figure 2 of the drawings, or, in other words, in aposition with its head 10 at that end of the cylinder to which the head7 is fitted. The movement of the piston 9 under the influence of thespring is limited by the engagement ofthe head 15 u on the outer end ofthe piston stem with t e end of the stuffing box 13, and in order thatthere will be no suction or compression resistance to movement of thepiston, vent openings 16 are preferably provided in the head 7 of thecylinder. The numeral 17 indicates a short arm which is secured to theupper end of the choke valve arm 4 and is provided with a series ofopenings 18 into which one end of a threaded stud 19 may beinterchangeably fitted, and a sleeve 20 is threaded onto this stud andis provided with an opening 21 extending diametrically thereof andaccommodating one end of a rod or wire 22, the other end of which isconnected, as at 23, to an eye provided upon the outer side of the head15 of the piston stem 11. A set screw 24 is threaded into the sleeve 20and is adapted to be tightened to bind the said rod the starter for theengine is operated, or the vengine is cranked, the suction created inthe intake manifold will result in a partial vacuum being created in thecylinder 5 with the result that the piston will be moved longicreted inthe intake manifold will be in v cre sed and the piston 10 will be moved.to

i tion. Of course, when the englne is running tudinally in the cylinderagainst the tension of the said spring 14 so as to actuate the arm 4 andmove the valve toward an opened position.

As the engine picks up speed, the suction a fullyor substantiallyfullyopened posiand at a-relatively low speed, and one, for examplewishes to pick up quickly on the road, the acceleration of the enginewill reslilt in temporarily reducing the vacuum in the manifold and thespring 14 will move the piston to turn the choke valve, in a closingdirection, thus supplying a comparatively rich mixture to the engine andeffecting acceleration thereof until normal running conditions areresumed, whereupon the proper vacuum will be again established and thepiston will be again moved to adjust the valve `to a full open orsubstantially full open position.

In order to prevent too quick or too early movement of the piston underthe influence of the 'vacuum to open the choke valve,

means is provided which will now be ldescribed. The said means com risesa cylinder` 25 which is mounted pre erably upon the head 6 of thecylinder 5 and is placed'in communication with the interior of thecylinder 5 by way of` a port 26 formedy at the juncture of the saidcylinder 25 and the head 6, the head 6-at the point -where the cylinderl25 is located thereon beingvhollow and this likewise being the point orportion where Y the elbow 8 is connected. A pistony 27 is arrangedywithin the cylinder 25 and come prises a head 28 and a stem 29 whichlatter works through an opening 30 in a head 31 fitted onto the lowerend of the said cylinder 25 and having vent openings 32 formed therein.A bracket arm 33 is mounted upon the forward side of the cylinder 25 anda lever arm' 34 is pivoted, as at 35, yto the Vbracket arm and has pinand slot connection,

as at 36, with the lower end of the piston stem 29.- y The lever arm 34extends beneath the lower end of the cylinder 25 and thence upwardly inrear of the said cylinder, and is provided with a rearwardly extendinfinger 37, the upper side of which is provi ed with a series of rackteeth indicated by the numeral 38, which ,teeth are to frictionallycoact with the peripher of the head 15' upon the piston stem .11. t thispoint `it will be evident that reciprocation of the piston 27 in thecylinder 25 will result in up and down swingingmovement of the "arm orfinger 37 and a consequent raising and position when the engine is idleor under conditions where there is but little suction in the cylinder 5,and at such time the detent finger 37 is in lowered position and itsteeth are out of engagement with the periphery of the head 15.

rAt this point it will be understood that when the motor is rst startedthe suction first moves the piston upwardly so that the latch stripengages the disk 15 and retards movement of the piston, 10 until thesuction has increased suiiiciently to overcome the action of the latchand spring. Therefore, the choke valve will not be opened until after apriming charge has been drawn into the cylinders and the motor. beginsto fire, If the motor begins 'to labor, as when going up a hill, thesuction will be reduced sufficiently to allow the spring 14 to move thepiston 10 towards the head 7 andf the choke valve will be moved towardsa closed position, thereby causing a richer mixture to be fed to thecylinders until the speed of the motor and suction created are againnormal. When the motor is stopped, the eliminated suction and backpressure result in the latch returning to an inoperative position andthe spring 14 moving the piston to close the choke valve.

In order to provide auxiliary means to control movement of the pistonrod 11, there et member having one end formed with a longitudinallyextending slot 40 through which is secured a screw 41 threaded into theouter side of the head 6 of the cylinder 5.- Olie of the spaced portionsthus provided is turned outwardly at right angles to provide an ear 42which supports a linger 43 having a series ofteeth 44 formed along oneof its edges. A spring 45 is connected at one end -selectively with theteeth 44 andat its otherend to a U-shaped detent 46 which is slidablymounted upon the outer or rear portion of a rearward extension 47 of thesaid arm 39, this extension being. arcuate and, toward its rear end,being curved in a direction away from the path of movement of the head15, as best shown in Figure 2 of the drawings. The detent 46 is disposedto straddle the convex side of the extension 47 and a pin 48 is ttedthrough the side members of the yoke and rides against theconcave sideof said extension 47, and, in one position of the yoke, coacts with anabutment stud 49 which is carried by the extension 47 and projects fromthe concave side thereof. The spring 45 is connected at one -rear cornerof the yoke and when the pin 48 is in engagement with the stud 49, asshown most clearly in Figure 6, the pull exerted by the spring will cantthe yoke so that the rear edge of its connecting portion will engage theconvex side of the extension 47 and in this position of the yoke theforward side of its connecting portion will be in the path of movementof the head 15 upon the piston stem 11.` Where it is desiredto supply arelatively large volume of rich gas to the engine, the throttle isadjusted to halfway open position and the engine is turned over by thestarter or by cranking and at this time the partial vacuum created inthe cylinder 5 will ,tend to Y#effect movement of the piston 9 againstthe tension of the spring 14, but the engagement of the head 15 with thedetent 46 will result in a retarded movement of the piston due to theadditionall resistance offered by the spring 45. At this Stime, thedetent 46 will be moved along the extension 47 ofthe bracket arm until,due to the curvature of said extension, the headl 15 rides past thedetent. Where it 1s desired to supply only a relatively small volume ofstarter or bv cranking.

rich gas to the intake manifold of the enne, the throttle is opened toonly a slight iegree and the engine is turned over by the Having thusdescribed the I claim is: y 1. In combination -with an intakemaminvention, what fold for internal combustion engines and a having' anoutlet neck connecting it with the intake manifold of the engine, apiston working in the cylinder and influenced by suction created in theintake manifold to move in a direction 'to open the choke valve,

' means yieldably resisting'such movement of the piston, a secondcylinder in communication with the first mentioned cylinder, a pistonthe second mentionedy cylinder, a stem for ea h piston, a latch armpivotallyI connected vwith the second cylinder and connected'withthestem ofthe last mentioned J the sai .arm and havinga series of racteeth thereon for frictional coaction with the periphery of the discupon the stem of the said first mentioned piston.

2. In combination with an intake manifold Y for internal combustionengines and a carbureter connected therewith and havin0r a choke valveand an actuating lever therefor, a choke valve control comprising acylinder having an ,outlet neck connecting it with the intake manifoldof the engine, a piston working in the cylinder and influenced bysuction created -in the vintake manifoldto move inl a direction to openthe choke valve, means yieldably resisting such movement, a

bracket member mounted upon the cylinder` f a choke valve controlcomprising a cylinder having an outlet neck connecting it incommunication with the intake manifold of the engine, a piston workingin the cylinder and influenced by suction created in the intake solmanifold to move'in a direction to open the v choke valve, meansyieldably resisting such movement, a bracket member mounted upon thecylinder, a longitudinally curved finger extending Jfrom the bracketmember, a yoke vstraddling the said finger andmovable thereon andconstituting a. detent, a head upon the stem of the piston for coactionwith the said detent, a spring connected with the detent and with thebracket member and normally holding the detentin position for engagementby the head upon outward movement of the piston, and an. abutment uponthe saidfnger e oageable by part of the detent for limitingntihemovement of the detent to such position under the inuence of thespring.V v l v Intestimony whereof lI aiix my si ature.

Y ARTHUR M'..HARBISON. L. 5.]

